1. Field of the Invention
The present invention relates generally to solid material comminution, more particularly to a hand supported rotary comminutor with cooperating commininuting surfaces, and specifically to hand held mills for grinding spice, particularly peppercorns.
2. General Background
Hand held rotary mills are commonly utilized for comminution of whole grains of pepper, i.e. peppercorns. While commonly available in a ground state it is generally preferred that pepper be freshly ground, i.e. comminuted from whole grains, in order to obtain a flavor which is considered far superior to already ground pepper. Another advantage of freshly ground pepper is the capability of selecting the relative fineness or coarseness of the grind of pepper.
Hence while many spices are utilized during cooking, i.e. preparation of food for human consumption, in accordance with quantities established by a recipe and/or the experience, knowledge, and judgement of the cook or chef, i.e. the person preparing the food, both the amount and grind quality of pepper, particularly, is most commonly left to be determined by the diner, i.e. the consumer of the prepared food, immediately prior to consumption. Salt is also typically available for addition in accordance with the taste of the diner but proper preparation typically requires the use of salt in accordance with a recipe and the experience, knowledge, and judgement of the chef or cook. Pepper, alternatively, is typically added just prior to consumption and is, moreover, preferably ground to a degree of fineness according to the taste of the diner.
For all of these reasons it is common to grind pepper, particularly, immediately prior to consumption of a meal with the use of a pepper mill which is characterized by manual rotation of one of two cooperating comminuting surfaces, i.e. grinding surfaces. The peppercorns are gravity fed from a hopper type supply contained within the mill and the fineness of the grind is determined by adjustment of the space between the two grinding surfaces.
One grinding surface is fixed within a plane and the other is rotated by the application of torque upon a vertical shaft. The torque is transmitted by means of a pair of opposed flats upon the shaft engaged by a rotor with a correspondingly shaped central slot therethrough possessing two opposed flats. The rotor is fixed vertically with respect to the shaft and the spacing between the grinding surfaces adjusted with vertical displacement of the shaft by means of threading upon the top end of the same engaged by a nut. The rotor is disposed below the fixed grinding surface and the nut generally is located above the top portion or head of the mill which is rotationally displaceable with respect to the lower body of the mill which contains a supply of peppercorns within a hopper. Loosening of the nut therefore increases the spacing between the grinding surfaces, thereby effecting a coarser grind, and tightening of the nut decreases said spacing, thereby effecting a finer grind.
Since operation of the mill requires rotation of the head with which the adjustment nut is typically in contact the grind selected is commonly affected by usage; the grind typically becoming finer over time as the rotation of the head in operation is clockwise and both the nut and the threading upon the top end of the shaft invariably possess right handed threading. This unfortunate characteristic, along with all of the other specifics mentioned above are, of course, applicable to what is regarded as the most commonly known type of pepper mill. There are, moreover, several variations upon this most common and basic construction but these variations are considered to be largely ancillary to the fundamentals described. Perhaps the most significant of such variations is the use of a crank between the nut and the head of the mill which not only provides additional leverage in operation but permits continuous revolution of the hand in operation as opposed to the repeated cycle of grasping, turning, releasing and turning back of the hand in order to rotate the head of the mill.
The use of a crank, which is generally perpendicular to the shaft and possesses an upright handle which is rotationally pivoted in connection to the distal end of the crank in order to permit grasping of the same during revolution, is considered to possess one substantial shortcoming. Because the revolution of the handle about the axis defined by the shaft is within a plane the hand effecting said revolution must be maintained within said plane and therefore the entire arm, from the shoulder down, must be moved in a coordinated manner which is considered far more difficult than the repeated cycle of grasping, turning, releasing and turning back of one hand which motion requires only reciprocal twisting of the forearm. The operation of a cranked mill is hence considered far more difficult than operation of the basic mill earlier described, especially with regard to maintaining a stable vertical disposition of the mill and accurate dispersion of the ground pepper which aspect is considered significant. It is considered a common practice in restaurants, particularly, to utilize rather lengthy mills of the conventional type described above in order to more easily dispense pepper upon a diner's meal with accuracy. Cranked mills are considered, therefore, to be unusual for good reason though the crank permits continuous operation which increases the rate of grinding in comparison with the conventional hand held rotary mill construction which operation requires repetitive turning of the head of the mill with one hand while holding the mill with the other.
The rate at which a mill grinds pepper is considered to be quite significant to a restauranteur, caterer, or other professional purveyor of prepared food because, simply put, time is money. Another reason relatively large pepper mills are commonly utilized in restaurants is that the capacity is enlarged and hence the frequency of required peppercorn replenishment is reduced. Larger mills are also less likely to be lost to theft or misplacement which is considered a common problem in the often hectic operation of restaurant kitchens. One wishes neither to waste time looking for a pepper mill nor to expend more than the minimum time necessary to provide freshly ground pepper in either the preparation of food or in seasoning of the same to a diner's taste. It is also considered that certain dishes require a large amount of ground pepper for proper preparation. Peppered beef steak, for example, properly requires a veritable coating with freshly ground pepper and the time spent in grinding pepper in the preparation of a number of such dishes is considered to be significant indeed.
In addition to the time lost in operation of a conventional pepper mill, which is considered to be most significant to the concerns addressed by the present invention, there are also the ancillary matters of wasting time looking for a pepper mill, the relative difficulty of grinding, and the rather more complex matter regarding the adjustment of the grind, particularly with regard to the gradual drifting of the same toward a finer grind as a result of operation as described above which, incidentally, exacerbates the loss of time as a finer grind requires more time to dispense than a coarser grind for the same amount of pepper. Four salient aspects are hence recognized as foci of the present discussion: (1) rate of grind; (2) ease of operation; (3) locatability of the mill and; (4) adjustment of the grind which is further noted to encompass (a) resistance to unintended change; as well as: (b) quickness, (c) ease, and (d) accuracy, of effecting the desired quality of grind in adjustment.
It is considered that the diameter of a rotor utilized in grinding pepper is restricted by the fact that a rotary mill dispenses in a ring with a vacant center and that the mill will lose accuracy if the diameter is too large. For this reason increasing the diameter of the rotary grinding surface is not an option. A manual crank enables continuous operation but is considered awkward for the reasons discussed above. It is hence considered that only two means of increasing both the rate of grind and ease of operation are viable: powering the mill or using more than one grinding rotor. The following references accordingly represent the known prior art which disclose use of electrically powered drive, more than one rotor, and a means of adjustment other than threading of the drive shaft.
______________________________________ References Cited Patent No. Inventor Date Title ______________________________________ U.S. 2,795,382 Francesch 11 June 1957 Electric Coffee Mill U.S. 4,591,104 Bounds 27 May 1986 Condiment Mill UK 2 183 173 Griffen 3 June 1987 Condiment Grinder U.S. 4,685,625 Mazza 11 Aug 1987 Grinding Mill U.S. 4,709,865 Bounds 1 Dec 1987 Dual Condiment Mill U.S. 5,022,591 Sanders 11 June 1991 Cordless Pepper Mill U.S. 5,685,501 Wagner 11 Nov 1997 Portable Spice Mill U.S. 5,897,067 Tardiff et al. 27 Apr 1999 Spice/Pepper-Mill Adjustment Mechanism ______________________________________
Discussion of the References Cited
Francesch discloses a fly cutter type rotary blade driven by an alternating current (A.C.) motor in a hand held coffee mill which is plugged into an ordinary electric outlet in operation. Bounds '104 discloses a dual position adjustment for a manual single rotor hand held mill using a spring which acts upward against the base and downward upon the rotor, the shaft, a handle thus biasing the casing downward which is manually displaced upward from the base to enable rotation ninety degrees for filling the hopper and one hundred eighty degrees to select fine or coarse grinds as effected by four pairs of opposed steps of two different heights. Griffen discloses manual selection means for grinding condiment in either of two adjacent containers each having a vertical shaft grinding tool either engageable by an idler gear vertically displaceable upon a helical grooved shaft to select the drive or use of "dog clutches formed by (opposed) gear pairs".
Mazza discloses a single rotor electric grinding mill comprised of two sections attached bayonet style, i.e. with rotary lugs engaging inclined grooves, which includes rotary adjustment of the grind effected with a ring possessing a spoke fixed to a threaded sleeve mating a threaded shaft. Bounds '865 discloses a double rotor condiment mill selectively driven by manual means through gears operating according to the direction of rotation imparted, specifically utilizing a central drive gear engaging one of two opposed pairs of spur gears on each of two pivoting arms and then the other two spur gears depending on rotational direction. Sanders discloses a rechargeable electric single rotor pepper mill with frusto conical grinding head possessing flat trapezoidal lands and flutes controlled by a switch spring biased in the open state. Recharging is facilitated by a base unit fed by ordinary line A.C.
Wagner discloses an electric spice mill utilizing a grinding wheel with a shaft perpendicular to the drive shaft from the motor intended to be small enough to carry on one's person. The use of a wheel so oriented with an electric motor having fluted teeth pointed in the direction of rotation fed by a hopper is also specifically claimed. Tardiff et alli disclose a grind adjustment for a single rotor manual spice/pepper mill which uses a manually rotatable stepped spacer ring with notched inclined surfaces which acts against the grinding rotor opposedly biased by a coil spring to provide several fixed spacings of the rotor apart from the fixed grinding surface.
Statement of Need
The pertinent prior art, as represented by the references cited above, teaches the use of electricity, A.C., battery, i.e. direct current (D.C.), and rechargeable battery, i.e. A.C. and D.C., to power a pepper mill possessing a single rotor. The use of two rotors, each exclusively associated with one of two different adjacent material supplies and alternately selectable for drive manually, is also taught by said prior art. The use of alternately opposed steps to obtain either a fine or coarse grind and the use of a notched and stepped ring in order to obtain several qualities of grind, fine, medium, and coarse, is also taught.
In address of the limitations to the rate of grinding obtainable with a pepper mill discussed further above it was suggested that powering a mill would overcome the discontinuous operation of a conventional mill and the difficulties associated with a manually cranked mill. It was also noted that the diameter of the rotor utilized in grinding is restricted by the intended use wherein some accuracy regarding the food to be freshly peppered or otherwise spiced with a mill is necessary and the ring pattern of dispersion achieved by a rotary mill is a significant factor. It is observed that this limitation remains in the known prior art. The problems associated with adjustment of grind quality effected with a threaded drive shaft are considered to have been addressed with the provision of two or three discrete steps available for the spacing between the comminuting surfaces.
The limitation upon grinding rate imposed by use of a single rotor dedicated to a single hopper supply remains, in short, and no means for continuous adjustment of grind quality which avoids the shortcomings of a threaded drive shaft is known. A need is hence recognized for a pepper mill which overcomes the limitations imposed by the use of a single rotor dedicated to a given supply hopper and a further need is recognized for continuous adjustment of grind which does not rely upon a threaded drive shaft.